40. Pharmacology in Sport Flashcards
How do beta blockers work?
Inhibit B receptors to slow heart rate
How do beta blockers affect exercise
Decreases force and rate of heart
Decrease NP
Decrease vasodilation in skeletal muscle
Decrease airway diameter
Can increase accuracy in sports such as archery, darts, snooker and shooting
How can beta blockers affect asthma?
If they are unselective can block beta 2 receptors, constricting bronchioles
This is the site of action for asthma inhalers e.g. salbutamol
Atenolol- good, selective
propanalol- bad, non selective
How does exercise affect the actions of beta blockers
Exercise and beta blockers have opposing effects
Exericse works ot increase HR and BP but Beta blockers have the opposite effects
Studies have shown that beta blockers can reduce HR even in elite athletes
V02 max reduces as well as time to exhasution reduces
When can beta blockers become dangerous with regards to exercise?
When machines calculate aimed HR to train at they dont take into account the effects of the beta blockers
This can lead to patients exhausting themselves or training too hard and doing more damage than good
How do beta blockers affect the following cardiac parameters:
Resting HR
Exercise HR
Cardiac output
V02 max
Resting HR- Decreased by all types
Exercise HR- Decreased by all types, ess so by cardioselective
Cardiac output- Exercise either decreases or doesnt change
V02 max- acutely decreases but can increase durign chronic training
What effetcs do beta blockers have on parameters pertaining to metabolic activity:
Adipose tissue lipolysis
Muscle Triglyceride utilisation
Glycogenolysis
Potassium
Adipose tissue lipolysis- imapired by most beta blockers
Muscle Triglyceride utilisation- imapired by most non-selective agents
Glycogenolysis- impaired by non-selective agents
Potassium- post exercise levels lower
How can beta blockers be abused?
Can increase accuracy in fien motor events by decreasing blood flow to skeletal muscle in the arm and reducing tremor
What advice should come with beta blockers with regards to exercise
Adjust HR targetted training accordingly
Can increase sweat loss
Use cardioslective agents e.g. atenolol
Monitor dose and efectiveness as fitness improves
Why are diuretics used by atheltes?
In sports where it is beneficial to lose weight e.g. boxing
To excrete other illegal drugs
For an aesthetic effect- body builder
Why can diuretics be used at high altitudes?
Acetazolamide- Shifts respiratory alkolosis in mountain sickness
can cause acidosis in exercise
How does exercise affect diuretics
Can lead into large losses of water
Exercise causes potassium to move into blood vessels during depolorization
Adrenaline/noradrenaline help drive potassium back into cells
Thiazides can slightly increase risk of diabetes
Decrease skin blood flow
What are the different types of diuretics?
Thiazide- used for hypertension
Loop diuretics- lose large amounts of minerals
Potassium sparing- spares minerals
Carbonic anyhdrase inihibotrs- glaucoma
Why do diuretics cause a lowering of VO2 max
ADH acts to conserve water during exercise. Diuretics can overcome this
Loss of flud vauses decreases BP and higher HR and SV. This means ability to perfor, is compromised
Potassium can be lost leading to muscle fatigue
Is it possible to take diuretics before a weigh in and then rehydrate yourself before a fight
NO
Even after recovery subjects still show detromental effects
